Seat

ABSTRACT

A seat which can obtain a favorable sitting feeling using a fibrous structure is provided. A seat  1  is provided with a cushion body 11 comprising fibrous structures  4   a  to  4   d  and a seat frame  15  supporting the cushion body  11,  in which the fibrous structures  4   a  to  4   d  are formed by stacking a web  2  so that the web  2  extends along a thickness direction T of the fibrous structures, the cushion body  11  is formed so that the thickness direction T of the fibrous structure  4   a  is along a load direction applied on the cushion body  11  at sitting, and a stacking direction of the web  2  constituting the fibrous structure  4   a  is along a widthwise direction W of the cushion body  11.  Since the web  2  easily falls down along the widthwise direction W of the cushion body due to a load of a seat occupant, the cushion body as a whole is in a shape curved along the widthwise direction W around a region where the load is applied, and the body of the seat occupant is supported as if being surrounded from both sides in the widthwise direction W. Thus, the seat occupant can obtain a soft touch feeling.

TECHNICAL FIELD

The present invention relates to a seat, and in particular to a seatusing a fibrous structure composed of polyester fibers or the like, anda method of manufacturing the same.

BACKGROUND ART

Conventionally, a seat using a fibrous structure composed of polyesterfibers or the like as a cushion body has been known (for example, seePatent Document 1 cited below). The fibrous structure used in the seatdescribed in Patent Document 1 is formed by successively folding a webobtained by dispersing and incorporating thermally adhesive compositeshort fibers as an adhesive component into matrix fibers composed of aninelastic polyester crimped short fiber assembly in a standing statealong its longitudinal direction. That is, this fibrous structure isformed to have a predetermined thickness by folding the web in anaccordion shape.

In this seat, each of a seat portion and a seat back portion isconstituted by stacking a plurality of the fibrous structures to form acushion body and coating this cushion body with a cover. Accordingly, inthis seat, since the standing direction of the web (a thicknessdirection of the cushion body) is directed along a load direction duringsitting of a seat occupant, excellent ventilation is, of course,favorable, a proper hardness to a load direction is provided, and loadcan be dispersed. Therefore, this seat can provide a soft touch feelingwhich cannot be obtained by urethane conventionally used in general.

Patent Document 1: Japanese Patent Laid Open Publication No.1996(H08)-318066

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

Since the seat described in Patent Document 1 has a structure such thata longitudinal direction of the fibers extends along a load direction,it can support a sufficient load while maintaining a soft touch feelingas mentioned above. However, in the seat, since the longitudinaldirection (combing direction or web stacking direction) of theaccordion-shaped fibrous structure is disposed in the front and reardirection in the seat portion and in the vertical direction in the seatback portion, there is a region where the cushion body is hard to flex(or hard to sink) at sitting. Thus, in this seat, a somewhat hardsitting feeling is obtained from this region, and there is a fear that afavorable sitting feeling can not be felt. The problem of a conventionalseat disclosed in Patent Document 1 will be described in more detailreferring to the attached drawings.

FIG. 12 is an explanatory diagram illustrating an entire view of aconventional seat, and FIG. 13 is an explanatory diagram illustrating asectional shape of a cut-out region R in FIG. 12. As shown in FIG. 12,the conventional seat 101 comprises a seat portion 110 having a sittingsurface 110 a on which a seat occupant sits and a seat back portion 120on which the back of the seat occupant leans. The seat portion 110comprises a cushion body 111, a cover 113, and a seat frame 115. In thisfigure, a widthwise direction of the seat portion 110 is indicated by W,a lengthwise direction by L, and a thickness direction by T.

As shown in FIG. 13, in the cushion body 111 of this seat portion 110, aweb 102 is formed by being folded in an accordion shape. The foldingdirection, that is, the stacking direction of the web 102 extends alongthe lengthwise direction L of the seat portion 110 and crosses thewidthwise direction W at a right angle. When a seat occupant sits on thesitting surface 110 a of the seat portion 110, a force toward thevertically downward direction, that is, load in the vertically downwarddirection of the thickness direction T is applied on the cushion body111. Since the web 102 is in the standing state along the thicknessdirection T, the fibers are compressed in the load direction (that is,the vertically downward direction of the thickness direction T) uponreceipt of the load. Thus, a portion having received the load in thesitting surface 110 a is flexed in the load direction.

However, in this conventional seat 101, the longitudinal direction (thatis, the stacking direction) of the web 102 constituting the cushion body111 extends along the lengthwise direction L of the seat portion 110,while the lateral direction of the web 102 extends along the widthwisedirection W of the seat portion 110. Since the lengthwise direction L isthe stacking direction of the web 102 and there are many gaps betweenthe standing structure of the web 102, the web 102 easily falls downalong the lengthwise direction L centering on the region having receivedthe load. On the other hand, since the widthwise direction W is thedirection orthogonal to the standing structure of the web 102 (that is,the lateral direction of the web 102), there are few gaps and the web102 is hard to fall down in the direction along the widthwise directionW from the load center. Accordingly, the center part (A1 in FIG. 12) onwhich the load is applied and a peripheral portion (A2 and A3 in FIG.12) along its widthwise direction W of the seat portion 110 are largelyflexed, but a flexing amount is small in a region (B1, C1 in FIG. 12)far from the load center part along the lengthwise direction L and aregion (C1 in FIG. 12) to which the upper part on the back of thebuttocks abuts, so that a soft touch feeling such as surrounding thebody is lacking, and a favorable sitting feeling can not be obtained.

An object of the present invention is to provide a seat which can give afavorable sitting feeling using a fibrous structure with a predeterminedthickness folded in a standing state.

Means for Solving the Problem

A seat according to an embodiment of the present invention is a seatprovided with a cushion body made from a fibrous structure and a seatframe supporting the cushion body, in which the fibrous structure isobtained by stacking a web such that an extending direction of the webconforms with a thickness direction of the fibrous structure, andregarding the cushion body, the thickness direction of the fibrousstructure extends along a load direction applied on the cushion body atsitting, while the stacking direction of the web constituting thefibrous structure extends along the widthwise direction of the cushionbody.

Thus, according to the seat of an embodiment of the present invention,since the web is stacked so that the thickness direction of the fibrousstructure extends along the extending direction of the web, upon receiptof an external load caused by contact with the body of a seat occupantsuch as buttocks and back at sitting, the web falls down and largelyflexes in the load direction. Thus, it becomes possible to give a softtouch feeling to the seat occupant at sitting. Moreover, since the seatis formed so that the stacking direction of the web constituting thefibrous structure extends along the widthwise direction of the cushionbody, the web easily falls down along the widthwise direction of thecushion body by the load of the seat occupant. Thus, if the load isapplied on the cushion body due to sitting of the seat occupant, the webfalls down toward the widthwise direction centering on a region on whichthe load is applied, and the cushion body as a whole is brought into ashape curved in the widthwise direction around the region havingreceived the load. Accordingly, the body of the seat occupant issupported as if being surrounded from both sides in the widthwisedirection, by which the seat occupant can obtain the soft touch feeling.

The cushion body is supported by the seat frame on both side portions inthe widthwise direction.

Thus, since the seat of an embodiment of the present invention issupported by the seat frame on both side portions in the widthwisedirection of the cushion body, though the center part in the widthwisedirection is largely flexed toward the load direction, a flexing amounton both side portions is small. Thus, the body of the seat occupant issupported as if being surrounded from both sides in the widthwisedirection, by which the seat occupant can obtain the soft touch feeling.

Effect of the Invention

According to an embodiment of the present invention, since the web isformed so that the stacking direction of the web constituting thefibrous structure extends along the widthwise direction of the cushionbody, the web easily falls down along the widthwise direction of thecushion body by the load of the seat occupant, and thus, if the loadfrom the body of the seat occupant is applied on the cushion body due tositting of the seat occupant, the cushion body largely flexes centeringon the region on which the load is applied in the widthwise direction,and the body of the seat occupant is supported as if being surroundedfrom the both sides in the widthwise direction. Accordingly, the seatoccupant can obtain the soft touch feeling, by which a favorable sittingfeeling can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view of a seat according to an embodiment ofthe present invention.

FIG. 2 is an explanatory diagram of a fiber direction of a web accordingto an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a manufacturing step of a sheet-likefibrous structure according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of the sheet-like fibrous structurebefore stacked according to an embodiment of the present invention.

FIG. 5 is an explanatory view of a mold according to an embodiment ofthe present invention.

FIG. 6 is an explanatory diagram of a manufacturing step of a cushionbody according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of a manufacturing step of the cushionbody according to an embodiment of the present invention.

FIG. 8 is a sectional explanatory diagram of the cushion body accordingto an embodiment of the present invention.

FIG. 9 is an explanatory diagram illustrating a sectional shape of aregion R cut out in FIG. 1.

FIG. 10 is an explanatory diagram of the region S in FIG. 8 in anenlarged manner.

FIG. 11 is sectional views showing a state that a seat portion of a seathas been cut in a widthwise direction.

FIG. 12 is an explanatory diagram illustrating an entire view of aconventional seat.

FIG. 13 is an explanatory diagram illustrating a sectional shape of aregion R cut out from FIG. 12.

EXPLANATION OF REFERENCE NUMERALS

-   1: seat-   2: web-   4 a: first sheet-like fibrous structure (fibrous structure)-   4 b: second sheet-like fibrous structure (fibrous structure)-   4 c: U-shaped sheet-like fibrous structure-   4 d: protrusion type sheet-like fibrous structure-   10: seat portion-   10 a: sitting surface (load receiving face)-   10 b: back surface (non-load receiving face)-   11, 21: cushion body-   13, 23: cover-   15, 25: seat frame-   17: trim cord-   19: engagement portion-   20: seat back portion-   40: mold-   40 a: cavity-   41: first mold-   42: second mold-   43: steam hole-   50: high pressure steam molding machine-   61: driving roller-   62: hot air suction type heat treating machine-   101: seat-   102: web-   110: seat portion-   110 a: sitting surface-   111: cushion body-   113: cover-   115: seat frame-   120: seat back-   a: fiber constituting web-   b: lengthwise direction of web-   c: fiber direction constituting web-   θ: angle of lengthwise direction of fiber to lengthwise direction of    web

BEST MODE FOR CARRYING OUT THE INVENTION

One embodiment of the present invention will be explained below withreference to the drawings. Incidentally, parts, arrangements or the likeexplained below do not limit the present invention, and the presentinvention can be modified variously within the scope and spirit of thepresent invention.

FIG. 1 to FIG. 11 show an embodiment of the present invention, FIG. 1being an explanatory diagram of a seat, FIG. 2 being an explanatorydiagram of a fiber direction in a web, FIG. 3 being an explanatorydiagram of a manufacturing step of a sheet-like fibrous structure, FIG.4 being an explanatory diagram of the sheet-like fibrous structurebefore stacked, FIG. 5 being an explanatory diagram of a mold, FIG. 6and FIG. 7 being explanatory diagrams of a manufacturing step of acushion body, FIG. 8 being a sectional explanatory diagram of thecushion body, FIG. 9 being an explanatory diagram illustrating asectional shape of a region R cut out in FIG. 1, FIG. 10 being anexplanatory diagram illustrating the region S in FIG. 8 in an enlargedmanner, and FIG. 11 being sectional views showing a state that a seatportion of the seat has been cut in a widthwise direction thereof.

A seat 1 of the embodiment can be applied to a seat for a vehicle, atrain, an airplane or the like, and it may be also applied to variouschairs such as a business chair or a care chair. The seat 1 of thisembodiment is provided with a seat portion 10 and a seat back portion20, as shown in FIG. 1. The seat portion 10 and the seat back portion 20are respectively constituted such that cushion bodies 11 and 21 areplaced on seat frames 15 and 25 and the cushion bodies 11 and 21 arecoated with covers 13 and 23.

Regarding the cushion body of this embodiment, a forming step (a cushionbody forming step) thereof will be explained taking the cushion body 11of the seat portion 10 as an example. The cushion body 21 is also formedaccording to a similar method as the above. The cushion body 11 in thisembodiment is formed by forming a sheet-like fibrous structure as afibrous structure where a web 2 has been folded in a standing state (afibrous structure forming step) described later, cutting this sheet-likefibrous structure into fibrous structure pieces with predeterminedshapes to stack a plurality of cut fibrous structure pieces anddisposing the plurality of cut fibrous structure pieces in a mold 40formed with a plurality of steam holes 43 which are ventilation holes onits mold face (a fibrous structure disposing step), and performing highpressure steam molding in high pressure steam molding machine 50 inwhich the mold 40 has been clamped (a molding step).

First, the web 2 for forming the cushion body 11 of this embodiment willbe explained with reference to FIG. 2 and FIG. 3. The web 2 is oneobtained by dispersing and mixing matrix fibers composed of assembliesof inelastic crimped short fibers, and thermally adhesive compositeshort fibers having a melting point lower than that of the inelasticcrimped short fibers and having a melting point of at least 120° C. asan adhesive component.

The web 2 in this embodiment is one obtained by performing cottonblending of inelastic polyester crimped short fibers as the inelasticcrimped short fibers and the thermally adhesive composite short fiberscomposed of thermoplastic elastomer having a melting point lower than amelting point of polyester polymer constituting the inelastic polyestercrimped short fibers by 40° C. and inelastic polyester such that thefibers are mainly directed in a longitudinal direction of the web 2. Theweb 2 of this embodiment has a bulk property of at least 30 kg/m³ and itis formed with cubic fiber crossing points between the thermallyadhesive composite short fibers and between the thermally adhesivecomposite short fibers and the inelastic polyester crimped short fibers.

In this embodiment, hollow polyethylene terephthalate fibers with asingle yarn fineness of 12 deniers and a fiber length of 64 mm, whichhave a cubic crimp due to anisotropic cooling, are used as the inelasticpolyester crimped short fibers. As the inelastic polyester crimped shortfibers, the short fibers are made from ordinary polyethyleneterephthalate, polytrimethylene terephthalate, polybutyleneterephthalate, polyhexamethylene terephthalate, polytetramethyleneterephthalate, poly-1,4-dimethylcyclohexane terephthalate,polypivalolactone, or copolymer ester thereof, cotton blended materialof these fibers, composite fibers composed of two or more kinds of theabove polymer components, or the like can be used. Short fibers ofpolyethylene terephthalate, polytrimethylene terephthalate, orpolybutylene terephthalate of these short fibers are desirable. Further,potential crimped fibers composed of two kinds of polyethyleneterephthalate and polytrimethylene terephthalate whose inherentviscosities are different from each other or a combination thereof,where crimps have micro-crimps due to heat treatment or the like canalso be used.

Further, a sectional shape of the short fiber may be circular, oval,hyterotypic, or hollow. A thickness of this short fiber is in a range of2 to 200 deniers, especially, preferably in a range of 6 to 100 deniers.Incidentally, when the thickness of the short fiber is small, softnessincreases, but elasticity of the cushion body often lowers.

Further, when the thickness of the short fiber is excessively thick,handling easiness, especially, formability of the web 2 deteriorates.Furthermore, there is a possibility that, as the number of constituentfibers decreases excessively, the number of crossing points formedbetween the short fibers and the thermally adhesive composite shortfibers also decreases so that elasticity of the cushion body is hard todevelop and simultaneously durability lowers. Furthermore, texturebecomes excessively rough and hard.

In the embodiment, as the thermally adhesive composite short fibers,core/sheath type thermally melting composite fibers (a core/sheathratio=60/40: weight ratio) with a single yarn fineness of 6 deniers anda fiber length of 51 mm, which uses thermoplastic polyether esterelastomer with a melting point of 154° C. as a sheath component and usespolybutylene terephthalate with a melting point of 230° C. as corecomponent are used.

The thermally adhesive composite short fibers are composed ofthermoplastic elastomer and inelastic polyester. Then, it is preferablethat the former occupies at least ½ of a fiber surface. Regarding aweight ratio, it is appropriate that the former and the latter are in arange of 30/70 to 70/30 in a composite ratio. The thermally adhesivecomposite short fibers may be of a side by side type or of a sheath-coretype, but the latter is desirable. In the sheath-core type, theinelastic polyester constitutes the core, but the core may be concentricor eccentric. Especially, the eccentric type is more desirable becausecoil-like elastic crimps are developed.

As the thermoplastic elastomer, polyurethane elastomer or polyesterelastomer is desirable. Especially, the latter is appropriate. As thepolyurethane elastomer, polyol with a low melting point having a molarweight of about 500 to 6000, for example, dihydroxy polyether, dihydroxypolyester, dihydroxy polycarbonate, dihydroxy polyester amide, or thelike, organic diisocyanate with a molar weight of 500 or less, forexample, p,p-diphenylmethane diisocyanate, tolylene diisocyanate,isophorone diisocyanate, diphenylmethane diisocyanate hydride, xylylenediisocyanate, 2,6-diisocyanate methyl caproate, hexamethylenediisocyanate, or the like, chain extender with a molar weight of 500 orless, for example, polymer obtained by reaction with glycol, aminoalcohol, or triol are used. An especially desirable one of thesepolymers is polytetramethylene glycol as polyol, or polyurethane usingpoly-ε-caprolactone or polybutylene adipate. In this case,p,p′-diphenylmethane diisocynate is desirable as an organicdiisocyanate. Further, p,p′-bidihydroxy-ethoxy benzene and 1,4-butanediol are desirable as the chain extender.

On the other hand, as the polyester elastomer, polyether ester blockcopolymer obtained by performing copolymerization using thermoplasticpolyester as a hard segment and using poly (alkylene oxide) glycol as asoft segment, more specifically, temary copolymer composed of at leastone of dicarboxylic acids selected from aromatic dicarboxylic acid suchas terephthalic acid, isophthalic acid, phthalic acid,naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid,diphenyl-4,4′-dicarboxylic acid, diphenoxy-ethane dicarboxylic acid, or3-sodium sulfoisophthalic acid, alicyclic dicarboxylic acid such as1,4-cyclohexane dicarboxylic acid, aliphatic dicarboxylic acid such assuccinate, oxalic acid, adipic acid, sebacic acid dodecanedioic acid,dimer acid, ester-forming derivatives thereof, or the like; at least oneof diol components selected from aliphatic diol such as 1,4-butane diol,ethylene glycol, trimethylene glycol, tetramethylene glycol,pentamethylene glycol, hexamethylene glycol, neopentyl glycol, ordecamethylene glycol, or alicyclic diol such as 1,1-cyclohexandimethanol, 1,4-cyclohexan dimethanol, or tricyclodecane dimethanol,ester-forming derivatives thereof, or the like; and at least one of poly(alkylene oxide) glycol such as polyethylene glycol, poly (1,2- and1,3-propylene oxide) glycol, poly (tetramethylene oxide) glycol,copolymer of ethylene oxide and propylene oxide, copolymer of ethyleneoxide and tetrahydrofuran, or the like, where an average molecularweight is in a range of about 400 to 5000 is used.

Considering the aspect of the adhesiveness, temperature property, andstrength of the inelastic polyester crimped short fibers, blockcopolymerization polyether polyester using polybutylene terephthalate asa hard segment and using polyoxybutylene glycol as a soft segment isdesirable. In this case, the polyester component constituting the hardsegment includes terephthalic acid as the main acid component, andpolybutylene terephthalate which is butylene glycol component as themain diol component. Of course, a portion (generally, 30 mol % or less)of this acid component may be replaced with another dicarboxylic acidcomponent or oxycarboxylic acid component, and similarly a portion(generally, 30 mol % or less) of the glycol component may be replacedwith a dioxy component other than the butylene glycol component.

Further, the polyether portion constituting the soft segment may bepolyether replaced with a dioxy component other than butylene glycol.Incidentally, various stabilizers, ultraviolet absorbent, thickeningbranching agent, delusterant, colorant, or other various improvers orthe like may be blended in the polymer according to necessity.

It is preferable that the degree of polymerization of the polyesterelastomer is in a range of 0.8 to 1.7 dl/g, especially, in a range of0.9 to 1.5 dl/g regarding inherent viscosity. If this inherent viscosityis excessively low, a heat adhesion spot formed by the inelasticpolyester crimped short fibers constituting the matrix is madebreakable. On the other hand, if the inherent viscosity is excessivelyhigh, a spindle-shaped node becomes hard to be formed at a heat adhesiontime.

As basic characteristics of the thermoplastic elastomer, a fractureelongation is preferably 500% or more, more preferably, 800% or more. Ifthis elongation is excessively low, when the cushion body 11 iscompressed and the deformation reaches the heat adhesion point, thecoupling at this portion becomes breakable.

On the other hand, an elongation stress of the thermoplastic elastomerat 300% elongation is preferably 0.8 kg/mm² or less, more preferably,0.8 kg/mm². If this stress is excessively large, it becomes hard for theheat-adhesion spot to disperse force applied on the cushion body 11, sothat, when the cushion body 11 is compressed, the heat-adhesion spot maybe broken by the force applied at that time, or even if it is notbroken, the inelastic polyester crimped short fibers constituting thematrix may be also strained or crimps may fatigue.

Further, the elongation recovery ratio of the thermoplastic elastomer at300% elongation is preferably 60% or more, more preferably, 70% or more.When this elongation recovery ratio is low, even if the cushion body 11is compressed so that the heat-adhesion spot is deformed, recovery toits original state may become hard. It is required that thesethermoplastic elastomers have melting points lower than the polymerconstituting the inelastic polyester crimped short fibers and they donot cause crimps of the crimped short fibers to thermally fatigue at ahot-melting processing time for forming the heat-adhesion spot.Therefore, the melting point is preferably lower than the melting pointof the polymer constituting the short fibers by 40° C. or more, morepreferably, by 60° C. or more. Such a melting point of the thermoplasticelastomer can be set to a temperature in a range of 120 to 220° C., forexample.

When the difference in melting point is smaller than 40° C., a heattreatment temperature at a melting processing time described later isexcessively high, and fatigue of crimps of the inelastic polyestercrimped short fibers is caused, which results in lowering of mechanicalproperties of the crimped short fibers. Incidentally, regarding thethermoplastic elastomer, when its melting point can not be observedclearly, a softening point thereof is observed instead of the meltingpoint.

On the other hand, as the inelastic polyester crimped short fibers usedas a mating component of the thermoplastic elastomer in the compositefibers, polyester polymers constituting the crimped short fibers formingthe matrix, such as described above, are adopted, but polyethyleneterephthalate, polymethylene terephthalate, or polybutyleneterephthalate is more preferably adopted among them.

The above-described composite fibers are dispersed and blended in arange of 20 to 100%, preferably, 30 to 80% based upon weight of the web2. In the web 2 in this embodiment, the thermally adhesive compositeshort fibers as the binder fibers and the inelastic crimped short fibersas the main fibers are cotton-blended at a weight ratio of 60:40.

When the dispersion and blend ratio of the composite fibers isexcessively low, the number of heat-adhesion spots is reduced, so thatthe cushion body 11 may become easily deformable, or elasticity,repulsive property, and durability may lower. Further, cracks betweentops arranged may occur.

In the embodiment, the inelastic polyester crimped short fibers and thethermally adhesive composite short fibers are cotton-blended at theweight ratio of 40:60, and they are formed in the web 2 of coatingweight 20 g/m² through a roller card.

The web 2 in this embodiment is formed such that a ratio of fibersoriented in the lengthwise direction of the web is relatively higherthan that of fibers oriented in a lateral direction. That is, the web 2in this embodiment is formed so as to satisfy a relationship of C≧3D/2,preferably, C≧2D per unit volume. When the total numbers of the fibers Coriented in the lengthwise direction (a continuous direction) in thiscontinuous web 2 and the fibers D oriented in the lateral direction (awidthwise direction of the web) are examined, it can be confirmed thatC:D=2:1.

Here, as shown in FIG. 2, the fibers oriented in the lengthwisedirection of the web 2 are fibers satisfying such a condition that anangle θ of the lengthwise direction of the fibers to the lengthwisedirection of the web is in a range of 0°≦θ≦45°, while the fibersoriented in the lateral direction (the widthwise direction of the web)are fibers satisfying such a condition that the angle θ is in a range of45°<θ≦90°. In the figure, reference symbol a represents fibersconstituting the web, reference symbol b represents the lengthwisedirection (extending direction) of the web, and reference symbol crepresents the fiber direction constituting the web. Further, regardingthe orientation of the fibers constituting the sheet-like fibrousstructure, a thickness direction of the sheet-like fibrous structure anda direction extending along a direction perpendicular to a thicknessdirection thereof mean directions within a range of ±45° to thesedirections.

A direction where each fiber direction can be observed by extractingrandom portions in a surface layer portion and an inner layer portion ofthe web 2 to observe them using a transmission type optical microscope.Incidentally, the thickness of the web 2 is 5 mm or more, preferably, 10mm or more, further preferably 20 mm or more. Generally, the web 2 has athickness of 5 to 150 mm.

Next, the web 2 formed such that fibers mainly extend along thelengthwise direction is folded like an accordion such that it has apredetermined density and a desired thickness as a structural body, sothat cubic fiber crossing points are formed between the composite fibersand between the inelastic polyester crimped short fibers and thecomposite fibers, and heat treatment is then performed at a temperature(to 80° C.) lower than the melting point of the polyester polymer andhigher than the melting point (or a fluidization start point) of thethermoplastic elastomer, so that elastomer components are melt-adheredat the fiber crossing points and flexible heat-adhesion spots areformed.

Specifically, as shown in FIG. 3, the web 2 is folded to an accordionshape by pushing the web 2 into a hot-air suction type heat treatmentmachine 62 (a length of a heat treatment zone is 5 m and a movingvelocity is 1 m/min) by a driving roller 61 with a roller surfacevelocity of 2.5 m/min and it is formed in a heat-adhered sheet-likefibrous structure with a thickness of 25 mm by treating the web 2 at190° C. for 5 minutes using Struto equipment (a fibrous structureforming step).

Adhesion spots thermally adhering in a state the thermally adhesivecomposite short fibers have crossed one another and adhesion spotsthermally adhering in a state that the thermally adhesive compositeshort fibers and the inelastic crimped short fibers have crossed oneanother are dispersed in the sheet-like fibrous structure thus formed.It is appropriate for developing cushioning properties, ventilationproperties, and elasticity that the density of the sheet-like fibrousstructure is in a range of 5 to 200 kg/m³.

By forming the web 2 formed such that their fibers extend along thelengthwise direction in a folding manner, the sheet-like fibrousstructure is formed such that the number of fibers oriented in thethickness direction is larger than that of fibers oriented in adirection perpendicular to this thickness direction and a direction ofthe fibers mainly becomes parallel to the thickness direction. That is,the sheet-like fibrous structure in the embodiment is formed such thatwhen the total number of fibers arranged along in the thicknessdirection is represented as A and the number of fibers arranged alongthe direction perpendicular to the thickness direction is represented asB regarding per unit volume, a relationship of A≧3B/2, preferably, A≧2Bis satisfied.

Next, the sheet-like fibrous structure is cut in a predetermined shape,and cut pieces are stacked in a vertical direction (a thicknessdirection T), as shown in FIG. 4. In this embodiment, four kinds ofsheet-like fibrous structures 4 a to 4 d including a first sheet-likefibrous structure 4 a, a second sheet-like fibrous structure 4 b, aU-shaped sheet-like fibrous structure 4 c with a U shape for forming abank portion of the cushion body 11, and a protrusion-shaped sheet-likefibrous structure 4 d for forming a protrusion portion to be slightlyprotruded between both thighs of a seat occupant are respectively cut inpredetermined shapes, the U-shaped sheet-like fibrous structure 4 c andthe protrusion-shaped sheet-like fibrous structure 4 d are sandwichedbetween the first sheet-like fibrous structure 4 a and the secondsheet-like fibrous structure 4 b. Incidentally, a widthwise direction ofthe cushion body 11, a lengthwise direction thereof, and a thicknessdirection thereof are represented as W, L, and T in FIG. 4,respectively.

In this embodiment, the first sheet-like fibrous structure 4 a and thesecond sheet-like fibrous structure 4 b having equivalent fiber materialand fiber density to those of the first sheet-like fibrous structure 4 aare stacked on its lower face. In this embodiment, the fiber density ofthe first sheet-like fibrous structure 4 a and the second sheet-likefibrous structure 4 b is in a range of 5 to 35 kg/m³ before thermalmolding. Incidentally, the first sheet-like fibrous structure 4 a andthe second sheet-like fibrous structure 4 b correspond to the fibrousstructure of the present invention.

As described above, the first sheet-like fibrous structure 4 a is formedof a sheet-like fibrous structure obtained by folding the web 2 obtainedby blending the main fibers and the binder fibers in a standing state.The first sheet-like fibrous structure 4 a is arranged on a side (anupper side in FIG. 4) of a sitting surface 10 a of the seat 1, and itserves to receive load from the body of a seat occupant directly orindirectly via a cover. The thickness of the first sheet-like fibrousstructure 4 a may be a desired thickness according to the shape of thecushion body 11. It is set to a desired thickness in a range ofapproximately 10 to 40 mm, for example. The direction of the firstsheet-like fibrous structure 4 a is determined so that the stackingdirection of the web 2 extends along the widthwise direction (Wdirection in the figure).

The second sheet-like fibrous structure 4 b is formed of a sheet-likefibrous structure made from substantially the same fiber material asthat of the first sheet-like fibrous structure 4 a. The secondsheet-like fibrous structure 4 b is arranged on the side (a lower sidein FIG. 4) of the seat frame 15 of the seat 1. The thickness of thesecond sheet-like fibrous structure 4 b may be also a desired thicknesssimilarly to the first sheet-like fibrous structure 4 a. The stackingdirection of the web 2 in the second sheet-like fibrous structure 4 bmay be such that the stacking direction of the web 2 is the widthwisedirection W similarly to the first sheet-like fibrous structure 4 a, butit is preferable that the direction is the lengthwise direction L,contrary to the stacking direction of the first sheet-like fibrousstructure 4 a. With such arrangement, the lateral directions of the webs2 in the first sheet-like fibrous structure 4 a and the secondsheet-like fibrous structure 4 b become orthogonal to each other, bywhich the web of the first sheet-like fibrous structure 4 a which hassunk upon receipt of a load is easily supported by the web of the secondsheet-like fibrous structure 4 b, and thus, the cushion body 11 does notflex excessively in the load direction and durability against fatigueand the like can be improved.

Between the first sheet-like fibrous structure 4 a and the secondsheet-like fibrous structure 4 b, the U-shaped sheet-like fibrousstructure 4 c and the protrusion-shaped sheet-like fibrous structure 4 dare disposed. The U-shaped sheet-like fibrous structure 4 c is a fibrousstructure for forming a bank portion of the cushion body 11 as will bedescribed later, and the protrusion-shaped sheet-like fibrous structure4 d is a fibrous structure for forming a protrusion portion of thecushion body 11.

These sheet-like fibrous structures 4 a to 4 d are stacked in theirthickness direction T. That is, stacking is performed such that adirection of fibers extends in a vertical direction. Further, holt-meltfilms, hot-melt unwoven cloths, hot-melt adhesives, or the like arearranged at portions where the sheet-like fibrous structures 4 a to 4 dabut on one another according to necessity.

The sheet-like fibrous structures 4 a to 4 d thus stacked are arrangedin a mold 40 such as shown in FIG. 5 and compressed (a fibrous structurearranging step). The mold 40 of this embodiment is composed of a firstmold 41 and a second mold 42. The first mold 41 is a mold used to form ashape of the cushion body 11 positioned on the side of the sittingsurface 10 a (namely, a surface), while the second mold 42 is a moldused to form a shape of the cushion body 11 positioned on the side ofthe seat frame 15, namely, on the side of a back surface 10 b (anon-load receiving face). When the first mold 41 and the second mold 42are fastened, a cavity 40 a having a desired undulation shape of thecushion body 11 is formed. Further, steam holes 43 are formed on aportion or a whole of a mold face of the mold 40. In the embodiment, thesteam holes are hardly formed on the first mold 41 while a plurality ofsteam holes 43 are bored over a whole face of the second mold 42 in thesecond mold 42. The mold 40 can be formed using such metal as iron,steel, aluminum, glass fiber, or carbon fiber, or it may be formed ofany synthetic resin.

FIG. 6 is a sectional view of a state that the sheet-like fibrousstructures 4 a to 4 d have been disposed in the mold 40 and the mold 40has been fastened. The sheet-like fibrous structures 4 a to 4 d areformed to be larger than the cavity 40 a of the mold 40 in a naturalstate by about 1.2 to 3.0 times in volume. Accordingly, the sheet-likefibrous structures 4 a to 4 d are changed to a state that they have beencompressed to the shape of the cavity 40 a at a mold fastening time.

The first sheet-like fibrous structure 4 a is received in the cavity 40a such that an upper face thereof abuts on an inner wall face of thefirst mold 41. Further, the second sheet-like fibrous structure 4 b isarranged in the cavity 40 a such that a lower face thereof abuts on aninner wall portion of the second mold 42. The U-shaped sheet-likefibrous structure 4 c and the protrusion-shaped sheet-like fibrousstructure 4 d are disposed between the first sheet-like fibrousstructure 4 a and the second sheet-like fibrous structure 4 b.

Next, as shown in FIG. 7, the mold 40 in which the sheet-like fibrousstructures 4 a to 4 d have been disposed is entered into a high pressuresteam molding machine 50. A steam introducing port (not shown) is formedon an upper portion of the high pressure steam molding machine 50, sothat high pressure steam can be introduced from the outside of the highpressure steam molding machine 50 into the high pressure steam moldingmachine 50. The mold 40 is installed in the high pressure steam moldingmachine 50 such that the second mold 42 is directed vertically upwardlyand the first mold 41 is directed vertically downwardly. After steam isblown to the mold 40, cooling and mold-releasing are performed to obtainthe cushion body 11 (cooling and mold-releasing step).

In the molding step of this embodiment, a temperature inside the highpressure steam molding machine 50 is controlled such that steam with amolding temperature can be blown to the molding 40. Here, the moldingtemperature is a temperature higher than a melting point of thethermally adhesive composite short fibers serving as the binder fibers,namely, higher than a melting point of thermoplastic elastomer, andlower than a melting point of matrix fibers (the inelastic crimped shortfibers) serving as the main fibers. In order to raise a temperature ofsteam to the molding temperature, a temperature inside the high pressuresteam molding machine 50 is first raised to the molding temperature by aheater (not shown) and a pressure inside the high pressure steam moldingmachine 50 is raised from an ambient air pressure (about 1 atm) to atleast saturated steam pressure of steam or higher in the moldingtemperature.

In this embodiment, since the melting point of the binder fibers isabout 154° C., the molding temperature is set to 161° C. that is higherthan the melting point. In this embodiment, then, since water vapor(H₂O) serving as heat conduction material is blown to the mold 40, thetemperature inside the high pressure steam molding machine 50 is raisedup to the molding temperature of 161° C. in about 30 seconds and thepressure inside the high pressure steam molding machine 50 is raised toair pressure of about 5.5 atm (about 0.557 MPa) which is a boiling pointat the molding temperature of 161° C. That is, the saturated steampressure at the molding temperature of 161° C. is about 5.5 atm.

In the molding step, water vapor with the molding temperature is blownto the mold 40 in a state that the temperature and the pressure insidethe high pressure steam molding machine 50 have been kept in the moldingtemperature and a predetermined pressure. In this embodiment, molding isperformed by blowing steam to the mold 40 for about one minute and 10seconds. Thereafter, the temperature inside the high pressure steammolding machine 50 is lowered to the molding temperature or lower inabout one minute and the pressure inside the high pressure steam moldingmachine 50 is reduced to an ambient air pressure. Then, the mold 40 istaken out of the high pressure steam molding machine 50 to be cooled (acooling step), and the cushion body 11 thermally molded is released fromthe mold 40 (a mold-releasing step). In this embodiment, tact time forthermally molding the cushion body 11 in the high pressure steam moldingmachine 50 can be set to about 3 to 5 minutes.

By blowing steam at the molding temperature to the mold in this manner,steam enters in the sheet-like fibrous structures 4 a to 4 d havingventilation properties from steam holes 43 of the mold 40, and it exitsfrom other steam holes 43 to the outside of the mold 40. The sheet-likefibrous structures 4 a to 4 d are disposed in the mold 40 in theircompressed state, and crossing points between the thermally adhesivecomposite short fibers and between the thermally adhesive compositeshort fibers and the inelastic crimped short fibers are caused tothermally adhere to one another due to steam heat so that the cushionbody is formed in the shape of the cavity 40 a of the mold 40.

Further, hot-melt films, hot-melt unwoven clothes, hot-melt adhesives,or the like disposed among the sheet-like fibrous structures 4 a to 4 dare melted due to steam heat and the sheet-like fibrous structures 4 ato 4 d are fixed to one another. Thus, fibers in the sheet-like fibrousstructures 4 a to 4 d are caused to thermally adhere to one another dueto steam and the sheet-like fibrous structures 4 a to 4 d are fixed toone another by the hot-melt film, a hot-melt unwoven cloth, hot-meltadhesive, or the like, so that a cushion body 11 with a predeterminedshape is formed. Incidentally, dish cloth may be inserted on a surfaceaccording to necessity, or wires made from steel or the like may beinserted among the sheet-like fibrous structures 4 a to 4 d.

When steam at the molding temperature is blown to the mold 40 inside thehigh pressure steam molding machine 50 raised up to the saturated steampressure like this embodiment, a molding time can be largely reduced.That is, since steam at the molding temperature has a thermal capacitylarger than that of hot air, the binder fibers can be melted in a shorttime.

Incidentally, when high pressure steam is blown to the mold under airpressure, since the high pressure steam adiabatically expandsimmediately and a temperature of the steam lowers, it is difficult tocause steam at the molding temperature to reach inside of the fiberbodies. Therefore, a long molding time is required notwithstanding.Further, in this embodiment, by largely shortening the molding time, atime when fibers are exposed to heat is shortened so that texture of thecushion body 11 molded is made excellent.

In the cushion body 11 of this embodiment, the sheet-like fibrousstructures 4 a to 4 d, where the directions of fibers are oriented inthe thickness direction T, are stacked and the high pressure steammolding is performed. Accordingly, the fibers constituting the cushionbody 11 are arranged along a direction in which load acts when a seatoccupant sits on the seat 1. With such a constitution, the cushion body11 in this embodiment has ventilation properties and can secure a properhardness to a stress direction, and it provides dispersibility of stressand excellent durability.

Further, the cushion body 11 in this embodiment is molded in a statethat it has been compressed by the mold 40, and it can take athree-dimensional and complicated undulation shape so as to conform withthe shape of the cavity 40 a of the mold 40. At this time, a cushioningfeeling can be adjusted partially according to a compression degree inthe mold 40.

The mold 40 in this embodiment is arranged such that the second mold 42is oriented vertically upwardly, namely, to the side of the steamintroducing port. Further, formation is made such that the steam holes43 of the second mold 42 outnumber the steam holes 43 of the first mold41. Therefore, an amount of steam introduced from the steam holes 43 ofthe second mold 42 into the cavity 40 a is more than the amount of steamintroduced from the steam holes 43 of the first mold 41. The steamintroduced from the steam holes 43 of the second mold 42 is exhaustedfrom the inside of the cavity 40 a through the steam holes formed on aside face of the second mold 42 or the steam holes formed on a side faceof the first mold 41. A flow of this steam is indicated by dotted arrowsin FIG. 7. Incidentally, in the mold 40 of this embodiment, any steamhole is not formed in a region of the first mold 41 corresponding to thesitting surface 10 a. Thereby, it is made possible to reduce thehardness of the sitting surface 10 a to provide a soft touch feeling toa seat occupant, as described later.

In this embodiment, since the amount of steam introduced from the secondmold 42 is more than the amount of steam introduced from the first mold41, a heat amount supplied to the second sheet-like fibrous structure 4b disposed on the side of the second mold 42 is more than a heat amountsupplied to the first sheet-like fibrous structure 4 a disposed on theside of the first mold 41. When the heat amount to be supplied is much,fibers are melted in a short time by the thermal molding and many fibersare fixed due to heat adhesion so that hardness becomes high. On theother hand, steam holes are hardly formed in the first mold 41 at all,and any steam hole is not formed on a region corresponding to thesitting surface. Therefore, the heat amount supplied to the firstsheet-like fibrous structure 4 a is low, and especially, the temperaturerise in the region corresponding to the sitting surface becomes veryslow. Thus, since the number of fibers fixed by the heat adhesion isreduced in the first sheet-like fibrous structure 4 a, hardness becomeslow.

As mentioned above, the first sheet-like fibrous structure 4 a becomeslower in surface layer hardness than the second sheet-like fibrousstructure 4 b, and a flexing degree of the former in the thicknessdirection T to a load due to sitting of a seat occupant becomes large.On the other hand, since the second sheet-like fibrous structure 4 bbecomes higher in hardness than the first sheet-like fibrous structure 4a, durability to load in the thickness direction T due to sitting can beimproved. Thus, a cushion body 11 including both a soft touch feelingduring sitting and durability to load due to sitting can be provided.

FIG. 8 is a sectional view of the cushion body 11 released from themold. FIG. 8 shows a sectional shape obtained by cutting the cushionbody 11 of the seat 1 shown in FIG. 1 along a direction of arrow lineA-A′. As shown in this figure, the cushion body 11 in this embodiment isone thermally molded in a state that the first sheet-like fibrousstructure 4 a, the second sheet-like fibrous structure 4 b, the U-shapedsheet-like fibrous structure 4 c with a U shape for forming a bankportion of the cushion body 11, and the protrusion-shaped sheet-likefibrous structure 4 d for forming a protrusion portion to be slightlyprotruded between both thighs of a seat occupant have been stacked inthe thickness direction T. Each of the sheet-like fibrous structures 4 ato 4 d is bonded to each other by hot-melt. In this embodiment, thefiber density of the first sheet-like fibrous structure 4 a and thesecond sheet-like fibrous structure 4 b after thermally molded is in arange of about 5 to 35 kg/m³.

FIG. 9 is an explanatory diagram illustrating a sectional shape of aregion R in a FIG. 1 cut out. As shown in this figure, in the cushionbody 11 in this embodiment, the web 2 is stacked by being folded in anaccordion-state, and the stacking direction extends along the widthwisedirection of the cushion body 11 (that is, the widthwise direction W ofthe seat 1). Thus, as shown in FIG. 10, in a region where a load F fromthe buttocks of a seat occupant is applied at sitting, upon receipt ofthe load in the thickness direction T, the web 2 falls down and iscompressed in the thickness direction T. Accordingly, the cushion body11 is largely flexed in the load direction along the widthwise direction(that is, the vertically downward direction of the thickness directionT) centering on the region where the load F is received. As shown inthis figure, the entire shape of the cushion body is largely flexed inthe load direction centering on the region where the load F is received,and in the peripheral region in the widthwise direction, a flexingamount is smaller than that in the center region of the load F, and acurved shape around the center region of the load F is formed as awhole. Thus, the body of the seat occupant is supported as if beingsurrounded by the cushion body 11 from both sides in the widthwisedirection. Accordingly, the seat 1 of this embodiment can give a softtouch feeling to the seat occupant.

Particularly, since even a region in contact with the back side of thethighs of the seat occupant (B1 in FIG. 1) and a region in contact withthe upper part on the back of the buttocks (C1 in FIG. 1) are flexedalong the widthwise direction upon receipt of the load, a soft touchfeeling as if surrounding the body from the both sides can be obtained,by which a favorable touch feeling that can not be obtained from theconventional seat can be gained.

Moreover, as shown in FIG. 1, both side portions in the widthwisedirection of the cushion body 11 are supported by the seat frame 15.Thus, though the center part of the cushion body 11 is largely flexed inthe load direction upon receipt of the load, since both side portionsare supported by the seat frame 15, downward flexing is regulated and aflexing amount in the load direction is small. Thus, the cushion body 11forms a largely curved shape along the widthwise direction from the loadcenter upon receipt of the load of the seat occupant. As a result, asoft touch feeling as if the body is surrounded by the cushion body 11from the both side portions can be given to the seat occupant.

Incidentally, in the text, a large flexing degree means a large degreeof deformation of the fibrous structure in the load direction inresponse to an applied load, and specifically it includes both a largedegree of reduction in the thickness caused by compression of thefibrous structure in the load direction due to load and a large degreeof bending of the entire shape of the plate-state fibrous structure inthe load direction. On the contrary, a small flexing degree means asmall degree of deformation of the fibrous structure in the loaddirection due to the applied load, and specifically it includes both asmall degree of reduction in the thickness caused by compression of thefibrous structure in the load direction due to load and a small degreeof bending of the entire shape of the fibrous structure in the loaddirection.

The U-shaped sheet-like fibrous structure 4 c is disposed between thefirst sheet-like fibrous structure 4 a and the second sheet-like fibrousstructure 4 b. The U-shaped sheet-like fibrous structure 4 c in thisembodiment is formed from approximately the same material as that forthe first sheet-like fibrous structure 4 a or the second sheet-likefibrous structure 4 b. Further, the protrusion-shaped sheet-like fibrousstructure 4 d is similarly disposed between the first sheet-like fibrousstructure 4 a and the second sheet-like fibrous structure 4 b. Theprotrusion-shaped sheet-like fibrous structure 4 d is also formed fromapproximately the same material as that for the first sheet-like fibrousstructure 4 a or the second sheet-like fibrous structure 4 b.Incidentally, in the cushion body 11 in this embodiment, the bankportion and the protrusion portion are formed using the U-shapedsheet-like fibrous structure 4 c and the protrusion-shaped sheet-likefibrous structure 4 d, but the bank portion or the protrusion portionmay be formed utilizing the shape of the cavity 40 a without using thesesheet-like fibrous structures.

Further, all of the first sheet-like fibrous structure 4 a, the secondsheet-like fibrous structure 4 b, the U-shaped sheet-like fibrousstructure 4 c, and the protrusion-shaped sheet-like fibrous structure 4d are formed from the same fiber material. Therefore, when the cushionbody 11 is discarded due to damage of the cushion body 11 or duration oflife, separation thereof can be saved, so that recycling efficiency isimproved.

Incidentally, in this embodiment, the example that one sheet-likefibrous structure 4 a and one sheet-like fibrous structure 4 b have beenstacked as the cushion body 11 is shown, but regarding each of thefibrous structures, the number of stacks may be plural. In this case, itis preferable that the number of fibrous structures to be stacked isadjusted according to feeling, durability, size, or the like requiredfor the cushion body 11.

Though the cushion body 11 has been explained above, a cushion body 21for the seat back portion may be similarly formed by stacking thesheet-like fibrous structures. Regarding the cushion body 21, adirection in which load acts from the back of the seat occupant when aseat occupant sits is a thickness direction of the sheet-like fibrousstructure constituting the cushion 21. Accordingly, in order to securedispersibility of hardness or stress and durability in a stressdirection, a three-dimensional shape can be achieved by stackingsheet-like fibrous structures in a direction in which stress acts andperforming high pressure steam forming within the mold. Then, a seat 1is formed by arranging the cushion bodies 11 and 21 thus formed on thesheet frames 15 and 25 and coating them with covers 13 and 23 (anassembling step).

In this embodiment, since also in the cushion body 21 of the seat backportion 20, the stacking direction of the web constituting thesheet-like fibrous structure is configured to extend along the widthwisedirection of the cushion body 21 similarly to the cushion body 11 of theseat portion 10, the back of the seat occupant is supported as if beingsurrounded from both sides in the widthwise direction. As a result, theseat occupant can obtain a soft touch feeling.

Incidentally, when the cushion body 11 is formed, the cover 13, and thesheet-like fibrous structures 4 a to 4 d are stacked via hot-melt films,hot-melt unwoven clothes, hot-melt adhesives, or the like, and they aredisposed in the mold 40, so that high pressure steam forming may beperformed. Thereby, the cover 13 can be formed integrally with thecushion body 11. The cover 23 may be similarly handled.

If the high pressure steam molding is performed in a state that thesheet-like fibrous structures 4 a to 4 d are coated with the cover 13,the sheet-like fibrous structures 4 a to 4 d and the cover 13 arearranged in the mold 40, when the molding temperature is excessivelyhigh, the cover 13 may lose color. In this case, therefore, the moldingtemperature may be set to be lower than the melting temperature of thedye dyeing the cover 13.

Further, in the above embodiment, water vapor is blown to the mold 40,but the present invention is not limited to this treatment and heatconducting material which does not adversely affect fibers can be used.That is, steam of the selected heat conducting material can be blown tothe mold 40 by raising pressure in the high pressure steam moldingmachine 50 such that a desired temperature is a boiling point of theselected heat conducting material.

Further, in the embodiment, the cushion body 11 is formed using thesheet-like fibrous structures 4 a to 4 d formed by folding the web 2 inan accordion shape as the fibrous structures, but the present inventionis not limited to this constitution, and a fibrous structure obtained bystacking many webs 2 in the thickness direction can be used as thefibrous structure, or a raw fiber assembly obtained by dispersing andblending main fibers and binder fibers may be used.

Furthermore, in the embodiment, the cushion bodies 11 and 21 obtained bystacking the sheet-like fibrous structures 4 a to 4 d to perform thehigh pressure steam forming are used for the seat portion 10 and theseat back portion 20, but the present invention is not limited to thisconstitution, and a cushion body obtained by stacking sheet-like fibrousstructures 4 a to 4 d to perform high pressure steam forming may be usedat a portion on which load due to seat occupant sitting acts such as anarm rest or a head rest.

Next, details of a seat using the cushion body 11 will be explained.FIG. 11 includes sectional views showing a state where a seat portion ofa seat has been cut in a widthwise direction, FIG. 11 (a) being a viewshowing the whole of the seat portion, and FIG. 11 (b) being a viewshowing a region circled in FIG. 11 (a) in an enlarged manner. As shownin FIG. 11 (a), the seat portion 10 includes a cushion body 11, a cover13, and a seat frame 15. A surface of the cushion body 11 is coated withthe cover 13, and as shown in FIG. 11 (b), a trim cord 17 made fromresin is sewn to an end portion of the cover 13. The trim cord 17 isformed to have an about J shape in section, and a member such as astring can be hooked on a bent portion formed at a distal end of thetrim cord 17. On the other hand, an engagement portion 19 is providedinside the seat frame 15 in a projecting manner. A wire is provided onthe side of a distal end of the engagement portion 19. The cover 13 canbe fixed to the seat frame 15 by hooking the bent portion of the trimcord 17 on the wire of the engagement portion 19.

Next, a method for manufacturing a seat portion 10 of a seat for avehicle will be explained in detail. First, a hot-melt film is caused toadhere to a surface of the cushion body 11 before the high pressuresteam forming, and the surface is coated with the cover 13. Next, thecushion body 11 whose surface is coated with the cover 13 is introducedinto a high pressure steam molding machine, wherein high pressure steammolding is performed so that the cushion body 11 and the cover 13 areformed integrally.

The molded cushion body 11 is taken out of the high pressure steammolding machine, and it is left for a while to dry. After drying, thetrim cord 17 made from resin is sewn on the end portion of the cover 13.Next, wrinkles of a surface of the seat portion 10 are removed bypulling the end portion of the cover 13 and the trim cord 17 is hookedto the engagement portion 19. The above is directed to explanation aboutthe seat portion 10 of the seat 1, but the seat back portion 20 can alsobe manufactured according to similar steps.

1-10. (canceled)
 11. A seat comprising: a cushion body made from afibrous structure, wherein the fibrous structure is obtained by stackinga web so that an extending direction of the web is along a thicknessdirection of the fibrous structure, wherein the thickness direction ofthe fibrous structure is along a direction of a load applied on thecushion body at sitting, and wherein a stacking direction of the webconstituting the fibrous structure is along a widthwise direction of thecushion body; and, a seat frame supporting the cushion body.
 12. Theseat according to claim 11, wherein the cushion body includes opposingside portions separated by a center portion along the widthwisedirection, and wherein the cushion body is supported by the seat frameon the side portions.
 13. The seat according to claim 11, wherein thecushion body comprises a molded cushion body resulting from being moldedby a mold having a cavity with a predetermined shape and by having steamblown to the fibrous structure through steam holes formed through themold under barometrical pressure higher than atmospheric pressure. 14.The seat according to claim 13, wherein the fiber structure comprisesbinder fibers and main fibers, and wherein the barometrical pressure isa saturated steam pressure at a temperature at or above a melting pointof the binder fibers and lower than a melting point of the main fibers.15. The seat according to claim 11, wherein the cushion body comprises amolded cushion body resulting from blowing steam to the fibrousstructure through steam holes through a side of a mold at a non-loadreceiving face of the cushion body.
 16. The seat according to claim 15,wherein the mold has more steam holes through the side of the mold atthe non-load receiving face of the cushion body than through a side ofthe mold at a load receiving face of the cushion body.
 17. A method offorming a seat comprising: molding a fibrous structure into a cushionbody by use of a mold having a cavity with a predetermined shape,wherein the fibrous structure is obtained by stacking a web so that anextending direction of the web is along a thickness direction of thefibrous structure, wherein the thickness direction of the fibrousstructure is along a direction of a load applied on the cushion body atsitting, wherein a stacking direction of the web constituting thefibrous structure is along a widthwise direction of the cushion body,and wherein the cushion body is molded by blowing steam to the fibrousstructure through steam holes formed through the mold under barometricalpressure higher than atmospheric pressure; and, supporting the moldedcushion body on a seat frame.
 18. The method according to claim 17,wherein the fiber structure comprises binder fibers and main fibers,wherein the barometrical pressure is a saturated steam pressure at atemperature at or above a melting point of the binder fibers and lowerthan a melting point of the main fibers.
 19. The method according toclaim 17, wherein the mold has a first face next to a non-load receivingface of the cushion body and a second face next to a load receiving faceof the cushion body, wherein the first face has steam holestherethrough, wherein the second face has steam holes therethrough, andwherein the cushion body is molded by blowing steam to the fibrousstructure through the steam holes in the first face.
 20. The methodaccording to claim 19, wherein the steam holes in the first face aremore numerous than the steam holes in the second face.
 21. A method ofmanufacturing a seat having a cushion body made from a fibrous structureand a seat frame supporting the cushion body, comprising at least:forming the fibrous structure by stacking a web so that an extendingdirection of the web is along a thickness direction of the fibrousstructure, wherein the thickness direction of the fibrous structure isalong a load direction of a load applied to the cushion body duringsitting, and wherein a stacking direction of the web constituting thefibrous structure is along a widthwise direction of the cushion body;disposing the fibrous structure in a mold having a cavity with apredetermined shape in a compressed state; thermally molding the fibrousstructure in the mold to form the cushion body; and, assembling thecushion body onto the seat frame.
 22. The method according to claim 21,wherein the cushion body comprises opposing side portions separated by acenter portion along the widthwise direction, and wherein the cushionbody is supported by the side portions of the seat frame.
 23. The methodaccording to claim 21, wherein the thermally molding of the fibrousstructure comprises blowing steam to the fibrous structure through steamholes formed through the mold under barometrical pressure higher thanatmospheric pressure.
 24. The method according to claim 23, wherein thefiber structure comprises binder fibers and main fibers, wherein thebarometrical pressure is a saturated steam pressure at a temperature ator above a melting point of the binder fibers and lower than a meltingpoint of the main fibers.
 25. The method according to claim 21, whereinthe mold has a first face next to a non-load receiving face of thecushion body and a second face next to a load receiving face of thecushion body, wherein the first face has steam holes therethrough,wherein the second face has steam holes therethrough, and wherein thethermally molding of the fibrous structure comprises blowing steamthrough the steam holes in the first face.
 26. The method according toclaim 25, wherein the steam holes in the first face are more numerousthan the holes in the second face.